EP3392142B1

EP3392142B1 - Deployable apparatus to prevent helicopter rollover

Info

Publication number: EP3392142B1
Application number: EP17182786.8A
Authority: EP
Inventors: Scott David Poster; Martin Peryea
Original assignee: Bell Helicopter Textron Inc
Current assignee: Bell Helicopter Textron Inc
Priority date: 2017-04-19
Filing date: 2017-07-24
Publication date: 2021-02-17
Anticipated expiration: 2037-07-24
Also published as: US11618588B2; US20210024226A1; CA2972723C; EP3715246A1; US20180305040A1; EP3392142A1; US10836511B2; CA2972723A1

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT OF FEDERALLY FUNDED RESEARCH

Not applicable.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of aircraft rollover, and more particularly, to a deployable apparatus to prevent helicopter rollover upon a water landing.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is described in connection with aircraft water landings.
One such example is taught in U.S. Patent No. 7,115,010, issued to Parrott, et al. , entitled "Floatation system including life raft". Briefly, a floatation system is disclosed for attachment to a helicopter landing skid that includes a girt dimensioned to be attached to a landing skid and a plurality of floats attached to the elongate girt, wherein the plurality of floats are adapted to be converted from a packed configuration to an deployed configuration, and wherein at least one of the plurality of floats extends beneath the elongate girt when the plurality of floats is in the deployed configuration.
Another example is taught in U.S. Patent No. 5,765,778, issued to Otsuka and entitled, "Flight vehicle with a safety device". Briefly, this inventor teaches an aircraft that is capable of safely landing during an emergency landing is disclosed. The aircraft has a safety device that includes a plurality of auxiliary engines, wherein each auxiliary engine is movable so as to vary the thrust axis in a range between a substantially horizontal direction and a substantially vertical direction. The safety device is said to also include a plurality of gas bags contracted and disposed at a lower portion of the aircraft body so as to be instantly expandable at a necessary time, such as during an emergency landing.
US9533757 discloses a buoyancy system for an aircraft, the buoyancy system being provided with at least one inflatable float. The buoyancy system has at least one inflator and at least one actuator interposed between said inflator and a float, said actuator having a cylinder and a rod partially received in said cylinder. Said rod is secured to a piston defining a first chamber within said cylinder and in fluid flow communication with the inflator, and a second chamber within said rod and in fluid flow communication with said float, and said piston has a channel to put the first chamber into fluid flow communication with the second chamber, said deployment device having a shutter for shutting said channel.

SUMMARY OF THE INVENTION

In one embodiment, the present invention includes an apparatus for preventing aircraft rollover upon a water landing as set out in claim 1. In one aspect, a first weight is also attached to the second end of the first boom. In another aspect, the apparatus further comprises a second deployable boom attached by a first end of the second boom to the aircraft and a second air bladder is attached to the second end of the second boom, wherein the second boom with the second deployable air bladder deploy upon a water landing. In another aspect, the apparatus further comprises a second boom attached by a first end of the second boom to the aircraft and that deploys substantially perpendicular to the longitudinal axis of the aircraft opposite the first boom, and a second air bladder and a second weight are attached to the second end of the second boom, wherein the second deployable air bladder and second weight deploys upon a water landing. In another aspect, one or more load attenuators are used to connect the first of the second air bladder to the boom, and wherein the one or more load attenuators comprise at least one of a "T" configuration, a "Z" configuration, a variable density of stiches, a fold and a plurality of stitches in the fold, a plurality of thread types, a tear-fabric, or a woven fabric. In another aspect, at least one of the first or the second booms are defined further as sponsons that deploy perpendicular to the longitudinal axis of the aircraft. In another aspect, the apparatus further comprises at least one of a deployable sail, a parachute or a weight or sea anchor that deploys from the tail boom upon water landing to provide a weathercock. In another aspect, the apparatus further comprises a deployable keel affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis and opposite a rotor of the aircraft upon a water landing, wherein the keel is sized to prevent aircraft rollover upon deployment.
Also described herein, according to an example not forming part of the present invention, is an apparatus for preventing aircraft rollover upon water landing comprising: a deployable keel affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis and opposite a rotor of the aircraft upon a water landing, wherein the keel is sized to prevent aircraft rollover upon deployment. In one aspect, the keel is affixed at either a front of the aircraft and fans out from back from front of the aircraft, of the keel is affixed to the rear of the aircraft and deploys from front to back. In another aspect, the keel is defined further as comprising a support and fabric, wherein the fabric deploys between the support and the aircraft. In another aspect, the keel is defined further as comprising weight at the end opposite the attachment of the keel to the aircraft. In another aspect, the apparatus further comprises at least one of a deployable sail, a parachute, sea anchor, or a weight that deploys from the tail rotor upon water landing to provide a weathercock. In another aspect, the apparatus further comprises a first, a second, or both a first and second deployable boom, each of the first boom, the second boom, or both being attached by a first end to the aircraft; and a first air bladder attached to a second end of the first boom; a second air bladder attached to the second end of the second boom, or both; wherein the first, the second, or both the first and second booms and the first, the second, or both, the first and second deployable air bladders, are deploy upon a water landing. In another aspect, the apparatus further comprises a first weight attached to a second end of the first boom, a second weight attached to a second end of the second boom, or both a first and a second weight attached to the first and second boom, respectively, wherein the first, the second, or both the first and second weights are deployed upon a water landing.
Also described herein, according to an example not forming part of the present invention, is an aircraft comprising: a plurality of air bladders that deploy around the aircraft upon a water landing; a first deployable boom affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis of the aircraft upon a water landing; and a first deployable air bladder attached to a second end of the boom, wherein the first deployable air bladder is configured to inflate when an aircraft lands in the water and prevent rollover of the aircraft, wherein deployment of the boom and first deployable air bladder prevents aircraft rollover upon water landing. In one aspect, a weight or sea anchor is also attached to the second end of the first boom. In another aspect, the apparatus further comprises a second boom attached by a first end of the second boom to the aircraft and that deploys substantially perpendicular to the longitudinal axis of the aircraft and opposite the first air bladder upon a water landing. In another aspect, the apparatus further comprises a second boom attached by a first end of the second boom to the aircraft and that deploys substantially perpendicular to the longitudinal axis of the aircraft opposite the first boom, and a second air bladder is attached to the second end of the second boom, wherein the second air bladder deploys upon a water landing. In another aspect, the apparatus further comprises a second boom attached by a first end of the second boom to the aircraft and that deploys substantially perpendicular to the longitudinal axis of the aircraft opposite the first boom, and a second air bladder and a sea anchor or weight are attached to the second end of the second boom, wherein the second air bladder deploys upon a water landing. In another aspect, the one or more load attenuators are used to connect the first of the second air bladder to the boom, and wherein the one or more load attenuators comprise at least one of a "T" configuration, a "Z" configuration, a variable density of stiches, a fold and a plurality of stitches in the fold, a plurality of thread types, a tear-fabric, or a woven fabric. In another aspect, at least one of the first or the second booms are defined further as sponsons that deploy perpendicular to the longitudinal axis of the aircraft. In another aspect, the apparatus further comprises at least one of a deployable sail, a parachute, sea anchor, or a weight that deploys from the tail rotor upon water landing to provide a weathercock.
Also described herein, according to an example not forming part of the present invention, is an aircraft comprising: a plurality of flotation air bladders that deploy around the aircraft upon a water landing; and a deployable keel affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis and opposite a rotor of the aircraft upon a water landing, wherein the keel is sized to prevent aircraft rollover.
In another embodiment, the present invention includes a method of preventing aircraft rollover as set out in claim 2.
In another aspect, the method further comprises adding a second boom attached by a first end of the second boom to the aircraft and that deploys substantially perpendicular to the longitudinal axis of the aircraft and opposite the first air bladder upon a water landing. In another aspect, the method further comprises adding a second boom attached by a first end of the second boom to the aircraft and that deploys substantially perpendicular to the longitudinal axis of the aircraft opposite the first boom, and a second air bladder is attached to the second end of the second boom, wherein the second airbladder deploys upon a water landing. In another aspect, the method further comprises adding a second boom attached by a first end of the second boom to the aircraft and that deploys substantially perpendicular to the longitudinal axis of the aircraft opposite the first boom, and a second air bladder and a weight are attached to the second end of the second boom, wherein the second air bladder deploys upon a water landing. In another aspect, the method further comprises adding one or more additional air bladders that deploy from the body of the aircraft, from a landing gear, or from a skid attached to the aircraft. In another aspect, at least one of the first or the second booms are defined further as sponsons that deploy perpendicular to the longitudinal axis of the aircraft. In another aspect, the method further comprises adding at least one of a deployable sail, a parachute, sea anchor, or a weight that deploys from the tail rotor upon water landing to provide a weathercock.
Also described herein, according to an example not forming part of the present invention, is a method of preventing aircraft rollover comprising: selecting a sea state and an aircraft, wherein the aircraft comprises an airframe fitting; sizing a deployable keel affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis and opposite a rotor of the aircraft upon a water landing, wherein the keel is sized to prevent aircraft rollover upon deployment. In another aspect, the method further comprises sizing a first, a second, or both a first and second deployable boom, each of the first boom, the second boom, or both being attached by a first end to the aircraft; and a first air bladder attached to a second end of the first boom; a second air bladder attached to the second end of the second boom, or both; wherein the first, the second, or both the first and second booms and the first, the second, or both, the first and second deployable air bladders, are deploy upon a water landing.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures and in which:

FIG. 1 shows a side view of an aircraft, specifically, a helicopter, for use of the present application;
FIG. 2 shows a rear view of an aircraft in which the helicopter has floats and a deployable boom deploys with a float to resist overturning moment;
FIG. 3 shows a rear view of an aircraft in which the helicopter has floats, a deployable boom, and sea anchor that deploys with floats to resist overturning moment;
FIG. 4 shows a rear view of an aircraft in which the helicopter has floats and dual deployable booms that deploy with floats to resist overturning moment;
FIG. 5 shows a rear view of an aircraft in which the helicopter has floats on sponsons that deploy outboard to resist overturning moment;
FIG. 6 shows a rear view of an aircraft not forming part of the invention in which the helicopter has floats and keel with a surface area that deploys with floats to resist overturning moment;
FIG. 7 shows a side view of an aircraft not forming part of the invention in which the helicopter has floats and a deployable apparatus or fan type object to resist overturning moment;
FIG. 8 shows a rear view of an aircraft not forming part of the invention in which the helicopter has floats, and a mass that deploys with floats to resist overturning moment;
FIG. 9 shows a side view of an aircraft not forming part of the invention in which the helicopter has floats and a deployable apparatus to encourage the aircraft to weathercock into the wind/waves; and
FIG. 10 shows a side view of an aircraft not forming part of the present invention in which the helicopter has floats and deployable apparatus to encourage the aircraft to weathercock into or away from the wind/waves.
FIG. 11 shows a flowchart of the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Illustrative embodiments of the system of the present application are described below.
In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present application, the devices, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as "above," "below," "upper," "lower," or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction.
This invention augments existing float kits designed for various helicopters. These float kits prevent the total loss of the aircraft after a water landing, but do not always prevent the aircraft from inverting after landing.
The deployable apparatus of the present invention would be added to the existing float kit of an aircraft. The deployable apparatus may include several features depending on application. One feature includes a long boom with a single float, the addition of a sea anchor for stabilization, a second boom on the opposite side, or combinations thereof. Another iteration of a deployable feature includes a keel or other object that deploys down into the water to resist the overturning moment, and/or a feature that orients it into the wind and waves. One or more of these deployable features can be included as a kit to attach to existing aircraft or built into a new aircraft.
FIG. 1 shows an aircraft 100 in accordance with a preferred embodiment of the present application. In the exemplary embodiment, aircraft 100 is a helicopter having a fuselage 102 and a rotor system 104 carried thereon. A plurality of rotor blades 106 is operably associated with rotor system 104 for creating flight. The system of the present invention can be used in conjunction with an aircraft 100. Although shown associated with a helicopter, it will be appreciated that the system of the present application could also be utilized with different types of rotary aircraft and vehicles whether they have one or more rotors. The tail rotor 110 is connected to the fuselage by tail boom 108.
FIG. 2 shows a rear view of an aircraft 100, shown as a helicopter 100, shown in the context of the fuselage 102, the tail rotor 110, and blades 106, and is floating on water 112 using float kits 114a and 114b, adjacent or about the fuselage 102. A first deployable boom 116 is connected to the fuselage 102 at first end 117, and is shown deployed, with the first air bladder 118 connected to second end 119 of the first deployable boom 116. The length of the first deployable boom 116, the size of the first air bladder 118, or both, are sized to at least partially float and to resist the overturning moment of the aircraft 100 when in the water 112. While the second end 119 is depicted as being below the waterline of water 112, the skilled artisan will recognize that it would also attach above the first air bladder 118. Likewise, the first end 117 of the first deployable boom 116 is depicted as being close to the waterline of water 112, but the skilled artisan will recognize that the first deployable boom 116 can attach to the fuselage 102 of the aircraft 100, it can attach at or about the tail boom 108.
FIG. 3 shows a rear view of an aircraft 100, shown as a helicopter 100, shown in the context of the fuselage 102, tail boom 108, tail rotor 110, and blades 106, and is floating on water 112 using float kits 114a and 114b, adjacent or about the fuselage 102. A first deployable boom 116 is connected to the fuselage 102 at first end 117, and is shown deployed, with the first air bladder 118 connected to second end 119 of the first deployable boom 116, and also a weight or sea anchor 120. The length of the first deployable boom 116, the size of the first air bladder 118, and/or the weight or sea anchor 120, are sized to at least partially float and sink and to resist the overturning moment of the aircraft 100 when in the water 112.
FIG. 4 shows a rear view of an aircraft 100, shown as a helicopter 100, shown in the context of the fuselage 102, tail boom 108, tail rotor 110, and blades 106, and is floating on water 112 using float kits 114a and 114b, adjacent or about the fuselage 102. A first deployable boom 116 is connected to the fuselage 102 at first end 117, and is shown deployed, with the first air bladder 118 connected to second end 119a of the first deployable boom 116. A second deployable boom 122 is connected to the fuselage 102, and is shown deployed, with the second air bladder 124 connected the second deployable boom 122, opposite the first deployable boom 116, and also connected at about first end 117. The length of the first and second deployable booms 116, 122, and the size of the first and second air bladders 118, 124, or both, are sized to at least partially float and to resist the overturning moment of the aircraft 100 when in the water 112. In this configuration, the first and second deployable booms 116, 122 are depicted at an angle θ from the longitudinal axis of the aircraft 100, however, the skilled artisan will recognize that another angle can vary, namely, the angle between the longitudinal axis (or centerline) of the aircraft 100 and the final position of the first and second deployable booms 116, 122 when viewed from the top. Generally, the first and second deployable booms 116, 122 can be perpendicular to the longitudinal axis (or centerline) of the aircraft 100, but the angle can also be more or less, depending on the configuration selected. While the second end 119a, 119b is depicted as being below the waterline of water 112, the skilled artisan will recognize that it would also attach above the first air bladder 118. Likewise, the first end 117 of the first deployable boom 116 is depicted as being close to the waterline of water 112, but the skilled artisan will recognize that the first deployable boom 116 can attach to the fuselage 102 of the aircraft 100, it can attach at or about the tail boom 108.
FIG. 5 shows a rear view of an aircraft 100, shown as a helicopter 100, shown in the context of the fuselage 102, tail boom 108, tail rotor 110, and blades 106, and is floating on water 112 using float kits 114a and 114b, adjacent or about the fuselage 102. A first deployable boom 116 is connected to the fuselage 102 at first end 117a, and is shown deployed, with the first air bladder 118 connected to second end 119a of the first deployable boom 116 in the form of a deployable sponson. A second deployable boom 122 is connected to the fuselage 102 at first end 117b, and is shown deployed, with the second air bladder 124 connected the second deployable boom 122 at the second end 119b, opposite the first deployable boom 116, also in the form of the deployable sponson. In this configuration, the two float kits 114a and 114b can be either optional, or can become the first and second deployable booms 116, 122. In this embodiment, the sponsons are shown above the waterline, however, the ends 119a, 119b could also be angled and be above, at, or below the waterline.
FIG. 6 shows a rear view of an aircraft 100, shown as a helicopter 100, shown in the context of the fuselage 102, tail boom 108, tail rotor 110, and blades 106, and is floating on water 112 using float kits 114a and 114b, adjacent or about the fuselage 102. In this configuration, a keel 130 is depicted in the deployed position and serves to resist the overturning moment by preventing fuselage rotation of the aircraft 100, by providing extra weight, or both.
FIG. 7 shows a side view of an aircraft 100, shown as a helicopter 100, shown in the context of the fuselage 102, tail boom 108, tail rotor 110, and is floating on water 112 using float kit 114a and a forward float kit 114c, adjacent or about the fuselage 102. In this configuration, a keel 130 is depicted in the deployed position and serves to resist the overturning moment by preventing fuselage rotation of the aircraft 100, by providing extra weight, or both. In this configuration, the keel deploys from the back to the front of the aircraft 100 and may include a fan 132, which can be, e.g., fabric, polymer, or other generally lightweight but strong material.
FIG. 8 shows a rear view of an aircraft 100, shown as a helicopter 100, shown in the context of the fuselage 102, tail boom 108, tail rotor 110, and blades 106, and is floating on water 112 using float kits 114a and 114b, adjacent or about the fuselage 102. In this configuration, a keel beam, or cable 130 is depicted in the deployed position and serves to resist the overturning moment by preventing fuselage rotation of the aircraft 100, by providing a weight 134, which would be sized and provide sufficient weight to resist the overturning moment of the aircraft 100 in water 112, but would not overwhelm the air bags from float kits 114a and 114b.
FIG. 9 shows a side view of an aircraft 100, shown as a helicopter 100, shown in the context of the fuselage 102, tail boom 108, and tail rotor 110, and is floating on water 112 using float kit 114a and a forward float kit 114c, adjacent or about the fuselage 102. In this configuration, a sail 136 deploys from the tail rotor 110, to weathercock the aircraft 100 into the wind/waves.
FIG. 10 shows a side view of an aircraft 100, shown as a helicopter 100, shown in the context of the fuselage 102, tail boom 108, tail rotor 110, and is floating on water 112 using a float kit 114a and a forward float kit 114c, adjacent or about the fuselage 102. In this configuration, a parachute 138 deploys from the tail rotor 110 and a sea anchor or weight 140, which may or may not be below the surface of the water 112. The parachute 138 and/or sea anchor or weight 140 help weathercock the aircraft 100 into the wind/waves. Instead of the parachute 138, the weathercocking can be the results of a combination of a sail 136 (not shown) and sea anchor or weight 140, or just the sea anchor or weight 140.
FIG. 11 is a flowchart 200 that shows the basic steps of the present invention. In first step 202, a first boom is sized for deployment and to prevent rollover of an aircraft that contacts water, wherein the first boom is affixed by a first end to the aircraft and the first boom is capable of deployment substantially perpendicular to a longitudinal axis of the aircraft upon a water landing. In step 204, the size of a first air bladder is selected to prevent roll-over of the aircraft upon water landing, wherein the first air bladder is attached to a second end of the first boom. In step 206, upon water landing, deploying the boom and first air bladder prevents aircraft rollover. Finally, in step 208, the air bladder is inflated when an aircraft lands in the water and prevents rollover of the aircraft.
It will be understood that particular embodiments described herein are shown by way of illustration and not as limitations of the invention.

Claims

An aircraft (100) having a plurality of float kits (114a, 114b) that prevent a total loss of the aircraft (100) after a water landing, the aircraft (100) further comprising:
an apparatus for preventing aircraft rollover, the apparatus comprising:
a first deployable boom (116) that is deployable in addition to the plurality of float kits (114a, 114b), wherein the first deployable boom (116) is affixed by a first end (117) to the aircraft (100) and capable of deployment substantially perpendicular to a longitudinal axis of the aircraft (100); and

a first deployable air bladder (118) attached to a second end (119) of the first deployable boom (116), wherein the first deployable air bladder (118) is configured to inflate when the aircraft (100) lands in the water, wherein deployment of the first deployable boom (116) and first deployable air bladder (118) prevents aircraft rollover upon water landing.
A method of preventing aircraft rollover comprising:
selecting a sea state and an aircraft (100), wherein the aircraft (100) comprises an airframe fitting and comprises a plurality of float kits (114a, 114b)) that prevent a total loss of the aircraft (100) after a water landing;

sizing at least a first deployable boom (116) affixed by a first end (117) to the aircraft (100) wherein the first deployable boom (116) is deployable in addition to the plurality of float kits (114a, 114b) and capable of deployment substantially perpendicular to a longitudinal axis of the aircraft (100) upon a water landing; and

selecting a first deployable air bladder (118) attached to a second end (119) of the first deployable boom (116), wherein the first deployable air bladder (118) is configured to inflate when the aircraft (100) lands in the water and prevents rollover of the aircraft (100), wherein deployment of the first deployable boom (116) and first deployable air bladder (118) prevents aircraft rollover upon water landing.
The aircraft (100) of claim 1, wherein a weight or a sea anchor (140) is also attached to the second end (119) of the first deployable boom (116); or
the method of claim 2, further comprising adding a sea anchor or a weight (140) is also attached to the second end (119) of the first deployable boom (116).
The aircraft of claim 1, further comprising a second deployable boom (122) that is deployable in addition to the plurality of float kits (114a, 114b), wherein the second deployable boom (122) is configured to be attached by a first end (117) of the deployable second boom (122) to the aircraft (100) and that deploys substantially perpendicular to the longitudinal axis of the aircraft (100) and opposite the first deployable air bladder (118) upon a water landing; or
the method of claim 2, further comprising adding a second deployable boom (122) that is deployable in addition to the plurality of float kits (114a, 114b), wherein the second deployable boom (122) is attached by a first end (117) of the second deployable boom (122) to the aircraft (100) and that deploys substantially perpendicular to the longitudinal axis of the aircraft (100) and opposite the first deployable air bladder (118) upon a water landing.
The aircraft of claim 1, further comprising a second deployable air bladder (124) attached to the second end (119) of the second deployable boom (122), wherein the second deployable air bladder (124) deploys upon a water landing; or
the method of claim 2, further comprising a second deployable air bladder (124) attached to the second end (119) of the second deployable boom (122), wherein the second deployable air bladder (124) deploys upon a water landing.
The aircraft of claim 5, further comprising a second weight (130) attached to the second end (119) of the second deployable boom (122), wherein second weight (130) deploys upon a water landing; or
the method of claim 5, further comprising a second weight (130) attached to the second end (119) of the second deployable boom (122), wherein second weight (130) deploys upon a water landing.
The aircraft of any preceding aircraft claim; or the method of claim 2, or the method of claim 3, wherein at least one of the first or the second deployable booms (116, 122) are defined further as sponsons that deploy perpendicular to the longitudinal axis of the aircraft (100).
The aircraft of claim 1, comprising at least one of a deployable sail (136), a parachute (138), sea anchor (140), or a weight that is operable to deploy from a tail boom (108) at or about a tail rotor (110) upon water landing to provide a weathercock; or
the method of claim 3, further comprising adding at least one of a deployable sail (136), a parachute (138), sea anchor (140), or a weight that is operable to deploy from a tail boom (108) at or about a tail rotor (110) upon water landing to provide a weathercock.
The aircraft of any preceding aircraft claim, further comprising a deployable keel (130) configured to be affixed by a first end to the aircraft (100) and capable of deployment substantially perpendicular to a longitudinal axis and opposite a rotor (106) of the aircraft upon a water landing, wherein the keel (130) is sized to prevent aircraft rollover upon deployment.
The aircraft of claim 9, wherein the keel (130) is configured to be affixed at either a front of the aircraft and fans out from back from front of the aircraft (100), or the keel (130) is configured to be affixed to a rear of the aircraft (100) and deploys from front to back.
The aircraft of claim 9, or of claim 10, wherein the keel (130) is defined further as comprising a support and fabric, wherein the fabric deploys between the support and the aircraft (100), and/or wherein the keel (130) is defined further as comprising weight at the end opposite the attachment of the keel (130) to the aircraft (100).